Pain Intensity and Opioid Utilization in Response to CPAP Therapy in Veterans with Obstructive Sleep Apnea on Chronic Opioid Treatment

Study Objectives: Sleep fragmentation has been linked to poor pain tolerance and lowered pain threshold. Little evidence exists on whether continuous positive airway pressure (CPAP) adherence in veterans with obstructive sleep apnea (OSA) who are taking opioids for non-malignant pain would ameliorate pain and reduce consumption of opioids. Methods: A retrospective case-control study was performed at a VA sleep center. Pain intensity was assessed using the Numerical Categorical Scale prior to CPAP treatment and 12-mo follow-up. Opioids intake was assessed using the morphine equivalent daily dose (MEDD). Adherence to CPAP was evaluated with the built-in meter. Results: We reviewed 113 patients with OSA (apnea-hypopnea index [AHI] 35.9 +/- 29.5) using a MEDD of 61.6 mg (range 5-980 mg) and a control group of 113 veterans with OSA (AHI 33.4 +/- 27.3) on no opioids treatment. CPAP adherence was significantly lower at 12 mo in opioid-treated patients compared to controls (37% versus 55%; p = 0.01). Greater pain intensity was the only independent variable associated with CPAP non-adherence at 12-mo follow-up (p = 0.03). Compared to baseline, no significant difference was observed in pain intensity or consumption of opioids in CPAP adherent patients. Conclusions: CPAP treatment did not reduce pain intensity or consumption of opioids in veterans with chronic pain who have coexisting OSA. CPAP adherence was lower in opioid-treated veterans with OSA compared to opioid-free veterans with OSA. Pain intensity was the only determinant of CPAP adherence. Future studies are needed to evaluate pain management program on adherence to CPAP.